I will be adding more, Also these were based upon cs:s not hl2:dm !

Hook color
Auto Ban on Names
Auto Change on Names
Team slapping
Team slaying
Different Slay Effects (ex. Lighting, Flash, Explosion, etc.)
Stacking
Stacking Certain Players
Auto Noclip Stuck Players From Being Stacked
Blinding
Blind Amount Alpha (ex. 0 - Nothing 255 - Everything)
Sticking People In The Ground
Fov
Fov Fuckup For Caged Players
Center Say
Private Say
Say Colors RGB (ex. 75 75 75 For Grey)
Perma Server Sprays
Give all weapons
Score Changing
Infinite Money
Infinite Ammo
All Talk Voting
Gravity Voting
Custom Question Votes (ex. Is PLAYER A Good Admin?)
Cage Voting
Voting Colors
Blind With White Rather Than Black
Server Help (ex. !Server or !Rules, !Admins, etc)
Glowing
Team based glowing
Best Player Glow
RGB Glowing
Infinite Grenades
Crowbars or Knifes (You Choose)
Adverts
Adverts Color
Different Area Adverts (ex. Center, Left, Chat, etc)
Hook Voting
Sounds on connect/disconnect
Teleporting
Setting perma Teleports
Play sounds when player sais a word matching
Kick all
Kick all but admins or clan members
Auto Response (ex. Admins - Admins Are Llama's Ass and Drunken Fool)
Llama Voice (ex. LlamaSound.wav)
Center Says with Sound
Team balancing
Cheat Detection (VAC SUCKS)
Auto Respawn
Freeze Team
Blind Team
Weapon Restriction
End OF Match Count Down
Slay Vote
Slay Team Vote
Slap Vote
Slap Team Vote
Stack Vote
Stack Team Vote
Stack Team
Flood Protection
Limited Spectator Use
Vote Cage
Vote Llama
Vote Gaging
Vote Muting
Roll The Dice
Log Commands
Force Quit
SV Commands Changing
Change Round Limit
Change Freeze Time
Change Money
Bot Adding
Bot Kicking
Vote On Bot Adding
Vote On Bot Kicking
Set Health
Set Armor

Many more will be added as the ideas come to mind.
I Also know that many of things plugins as of now are very hard to make or impossible. They are ment for the future of source op.